JMA (Japan Meteorological Agency) has operated the GMS (Geostationary Meteorological Satellite) and MTSAT (Multifunction Transport Satellite) series of satellites around the 140º east longitude to cover the East Asia and Western Pacific regions since 1978, and makes related contributions to the WMO's World Weather Watch (WWW) Program. As a follow-on to the MTSAT series, the Agency plans to operate next-generation satellites called Himawari-8 and Himawari-9 (himawari means "sunflower" in Japanese). Unlike the current MTSAT series, which performs both meteorological and aeronautical functions, to include air-traffic control communications and position information, Himawari-8 and -9 will have a dedicated meteorological mission. 1)2)3)4)5)6)

Currently (2014), MTSAT-2 (Himawari-7) is operational, while MTSAT-1R (Himawari-6) is on standby in orbit. MTSAT-2, which took over the Earth observation mission of MTSAT-1R on July 1, 2010, is scheduled to complete its observation operation in around 2015. In order to provide continuous observation services, JMA plans to commence its operation in 2015, when MTSAT-2 is scheduled to complete its period of operation. The Agency also plans to launch Himawari-9 in 2016.

Figure 1: Schedule for the follow-on satellites to the MTSAT series (image credit: JMA)

• EPS (Electrical Power Subsystem): The power generated is 2.6 kW, the bus voltage is 100 V, use of a Li-ion battery.

• MDHS (Mission Data Handling Subsystem): MDHS connects with the AHI instrument using SpaceWire I/F and processes the data from the instrument into telemetry, based on the CCSDS recommendations. The processed data are sent to the Ka-band transmission system. MDHS also connects with a satellite control system by SpaceWire and sends commands to AHI.

- Ku-band for TT&C services. The uplink rate is 500 bit/s, the downlink data rate is 15.36 kbit/s with a modulation PCM-PSK/PM

- Ka-band for payload data transmission. The data rate is 66 Mbit/s for AHI and 100 bit/s/300 bit/s for DCS. The modulation is QPSK, PCM-PSK, no encryption.

- UHF for DCS: The data rate is 100 bit/s/300 bit/s with a modulation of PCM-PSK.

For AHI data, compression is performed according to CCSDS Recommendation for Space Data System Standards. Lossless Data Compression, CCSDS 121.0-B-1 Lossless, May 1997.

Development status:

• On August 21, 2014, MELCO announced that it has completed work on the Himawari-8 satellite, the next generation geostationary meteorological satellite, based on a contract awarded by the JMA(Japan Meteorological Agency). Himawari-8 was delivered soon to Tanegashima Space Center, Japan, from where it was launched. 11)

Launch: The Himawari-8 spacecraft was launched on October 7, 2014 (05:16:00 UTC) on a H-IIA vehicle (H-IIA F25) from the TNSC (Tanegashima Space Center) of JAXA, Japan. The launch service provider was Mitsubishi Heavy Industries, Ltd. The launch vehicle flew as planned, and, at about 27 minutes and 57 seconds after liftoff, the separation of the Himawari-8 was confirmed. 13)14)15)

Orbit: Geostationary orbit of Himawari-8 and Himawari-9, altitude of ~35,800 km, longitude of ~140.7º east, covering the East Asia and Western Pacific regions, succeeding the GMS and MTSAT series.
Note: Himawari-8 and Himawari-9 orbit in close formation, both at around 140.7°E (in line with Japan, Papua and central Australia). This will offer the same view when operations are switched between the satellites.

Launch: The Himawari-9 spacecraft of JAXA was launched on November 02, 2016 (6:20:00 UTC) on the H-IIA F31 vehicle of MHI (Mitsubishi Heavy Industries) from the TNSC (Tanegashima Space Center), Japan. The launch vehicle flew as planned, and at approximately 27 minutes and 51 seconds after liftoff, the separation of Himawari-9 was confirmed. 16)

Both Himawari-8 and -9 spacecraft do not carry any equipment for direct data broadcasting. Hence, JMA is discussing the utilization of ICS (Internet Cloud Service) and CTS (Commercial Telecommunication Satellite) as data distribution services (Figure 6). JMA will substitute the CTS broadcasting for current MTSAT direct broadcasting. On the other hand, the Internet Cloud Service will be newly introduced as a means of data distribution for the National Meteorological and Hydrological Services (NMHSs) and for EUMETSAT. The agency will also introduce an Archive Server that is operated by the Japanese Science Group. Users of this server will be able to obtain all types of imagery from this server. Table 9 shows the receivable imagery products via the Internet Cloud Service / the CTS broadcasting. However, the types of imagery are limited for CTS broadcasting.

Himawari imagery in full-disk HRIT/LRIT files compatible with current MTSAT HRIT/LRIT data* is provided via the service. Files will be disseminated every 10 minutes in principle, but this interval will follow the MTSAT-2 observation schedule while MTSAT-2 is in operation. The number of bands of MTSAT-2 HRIT files is 5 out of 5, and that of Himawari-8 HRIT files is 14 out of 16.

* There is a slight difference between files disseminated via the MTSAT HRIT/LRIT services and those disseminated via the HimawariCast service. The former consist of lossless-compressed raw data and related headers. The latter are made up of non-compressed raw data and related headers, and the whole files are compressed using bzip2. See the links for details (HRIT, LRIT).
** Parallel bzip2 (pbzip2) commands are used for bzip2 compression.

The specification list of receiver for the CTS broadcasting is shown in Table 2. To receive imagery, the specification of equipment is needed. Note that the equipment for the current MTSAT direct broadcasting is not available for the CTS broadcasting.

• January 18, 2018: JMA has launched its new international HimawariRequest service, which allows National Meteorological and Hydrological Services (NMHSs) to request Target Area observation conducted by Himawari-8/9 every 2.5 minutes. 19)20)

- JMA's latest-generation Himawari-8 geostationary meteorological satellite began operation in July 2015, with the corresponding Himawari-9 unit entering a state of backup operation in March 2017. This dual satellite system is expected to provide a continuous stream of observation data for the Asia-Oceania region until 2029.

- AHI (Advanced Himawari Imager) on board Himawari-8/9 is capable of frequent and flexible observation, providing Full-Disk images of the Earth every 10 minutes and regional images with shorter intervals. Full-Disk and other regional observations have spatial resolutions of 0.5 to 2 km and spectral coverage incorporating 16 bands.

- In regional monitoring, Target Area observation provides imagery covering a 1,000 x 1,000 km area every 2.5 minutes with flexibility for location changes to support JMA's national and international services. The observation is normally focused on an area of active volcanoes in the domain of the Tokyo VAAC (Volcanic Ash Advisory Center), and is adapted to encompass typhoons within the responsibility area of the RSMC (Regional Specialized Meteorological Center) Tokyo Typhoon Center.

- The HimawariRequest service enables registered NMHS users to request particular Target Area observations in order to leverage this flexibility on an international scale. The service stems from a WMO RA II (Asia) regional project to develop support for NMHSs in satellite data, products and training in collaboration with WMO RA V (South-West Pacific) Members.

- JMA expects the HimawariRequest service to support disaster risk reduction activities in the region based on the monitoring of extreme events such as tropical cyclones and volcanic eruptions.

- Figure 23 shows the Target Area in the AHI observation sequence within a 10-minute time frame.

Figure 7: Target Area observation benefits (image credit: JMA)

Using the power of Japan's K computer, scientists from the RIKEN AICS (Advanced Institute for Computational Science) and collaborators have shown that incorporating satellite data at frequent intervals—ten minutes in the case of this study—into weather prediction models can significantly improve the rainfall predictions of the models and allow more precise predictions of the rapid development of a typhoon.

Weather prediction models attempt to predict future weather by running simulations based on current conditions taken from various sources of data. However, the inherently complex nature of the systems, coupled with the lack of precision and timeliness of the data, makes it difficult to conduct accurate predictions, especially with weather systems such as sudden precipitation.

As a means to improve models, scientists are using powerful supercomputers to run simulations based on more frequently updated and accurate data. The team led by Takemasa Miyoshi of AICS decided to work with data from Himawari-8, a geostationary satellite that began operating in 2015. Its instruments can scan the entire area it covers every ten minutes in both visible and infrared light, at a resolution of up to 500 meters, and the data is provided to meteorological agencies. Infrared measurements are useful for indirectly gaging rainfall, as they make it possible to see where clouds are located and at what altitude.

For one study, they looked at the behavior of Typhoon Soudelor (known in the Philippines as Hanna), a category 5 storm that wreaked damage in the Pacific region in late July and early August 2015. In a second study, they investigated the use of the improved data on predictions of heavy rainfall that occurred in the Kanto region of Japan in September 2015. These articles were published in Monthly Weather Review and Journal of Geophysical Research: Atmospheres.

For the study on Typhoon Soudelor, the researchers adopted a recently developed weather model called SCALE-LETKF—running an ensemble of 50 simulations—and incorporated infrared measurements from the satellite every ten minutes, comparing the performance of the model against the actual data from the 2015 tropical storm. They found that compared to models not using the assimilated data, the new simulation more accurately forecast the rapid development of the storm. They tried assimilating data at a slower speed, updating the model every 30 minutes rather than ten minutes, and the model did not perform as well, indicating that the frequency of the assimilation is an important element of the improvement.

To perform the research on disastrous precipitation, the group examined data from heavy rainfall that occurred in the Kanto region in 2015. Compared to models without data assimilation from the Himawari-8 satellite, the simulations more accurately predicted the heavy, concentrated rain that took place, and came closer to predicting the situation where an overflowing river led to severe flooding.

According to Miyoshi, "It is gratifying to see that supercomputers along with new satellite data, will allow us to create simulations that will be better at predicting sudden precipitation and other dangerous weather phenomena, which cause enormous damage and may become more frequent due to climate change. We plan to apply this new method to other weather events to make sure that the results are truly robust."

• On 24 January 2017, the first images from all 16 bands were captured by JMA's Himawari-9 geostationary meteorological satellite, which was launched on 2 November 2016. Testing and checking of the Himawari-9 system, including related ground facilities, are going well. Himawari-9 is scheduled to start operation in March 2017. 22)

• December 14, 2016: Himawari-8 Water Vapor (6.2 µm) images revealed the presence of a subtle packet of upper-tropospheric gravity waves propagating southeastward near the International Date Line (180º longitude over the central Pacific Ocean), just to the west/southwest of Midway Atoll on 14 December 2016 — and there were a few pilot reports of moderate to severe turbulence (which were responsible for at least one injury) in the general vicinity of this gravity wave feature from 1530 to 1740 UTC, at altitudes of 35,000 to 38,000 feet. 23)

• On November 11, 2016, the Himawari-9 satellite entered its geostationary orbit. 24)

• November 8, 2016: After in-orbit testing, Himawari-9 will stand by until 2022 as backup for the currently operational Himawari-8 geostationary satellite. HimawariCast users will not need to modify receiving system settings to continue data service usage even after the start of Himawari-9's operation. The combination of these two new-generation geostationary satellites will allow JMA to provide stable ongoing observation of the Asia and Pacific regions until 2029. 25)

• March 2016: According to JMA, the Himawari-8 spacecraft and its payload are operating nominally. 26)

• January 2016: The GSMaP (Global Satellite Mapping of Precipitation) product is a global rainfall map that is highly accurate, highly frequent, and high-spatial resolution through the development of rain rate retrieval algorithms based on reliable precipitation physical models by using a number of microwave radiometer (imagers, sounders, and imager/sounders) observation data, and comprehensive use of the Precipitation Radar (PR) on board the TRMM (Tropical Rainfall Measuring Mission) satellite. To produce a highly frequent global rainfall map, sampling errors caused by un-observed regions by LEO (Low Earth Orbit) satellites is a problem. The GSMaP project has developed a method to interpolate observations between each microwave imager by utilizing information from the Infrared imagers on board the five geostationary satellites, which are JMA's MTSAT/Himawari satellite, two NOAA's GOES satellites, and EUMETSAT's Meteosat satellites, and achieved production of an hourly global rainfall map in 0.1º latitude/longitude grid. 27)

- JAXA has provided the near-real-time GSMaP (GSMaP_NRT) product four hours after observation through the "JAXA Global Rainfall Watch" website (http://sharaku.eorc.jaxa.jp/GSMaP/) since 2008 as a prototype of the GPM (Global Precipitation Measurement) mission.

• Sept. 2, 2015: JAXA/EORC (Earth Observation Research Center) has released a new webpage, "JAXA Himawari Monitor" 28) , showing the color images and the quicklook images of the geophysical data from Himawari-8. 29)

- JAXA and JMA have exchanged the agreement on the distribution and the release of meteorological data. Under this agreement, EORC has released the data from Himawari-8 to research communities and has been creating the geophysical data that are consistent with JAXA's Earth observation satellites in order to release them widely to the general public. Other than releasing the images in the JAXA Himawari Monitor, EORC also stated to distribute via FTP the Himawari Standard Data and the geophysical data produced by JAXA.

- The Himawari Standard Data includes the visible to infrared radiances (Band 1 to 16) for three regions of Full Disk (global), Japan Area and Target Area. The observation data can be achieved every 10 minutes for Full Disk and every 2.5 minutes for Japan Area and Target Area. Using the observation bands that enable the world's first "color image" from geostationary satellite, one of the advanced aspects of Himawari-8, the JAXA Himawari Monitor shows the visible RGB composite images (Figure 10).

- In addition, for the Himawari geophysical data, JAXA/EORC produces the properties of atmospheric particles (called aerosols), such as desert dusts and PM2.5 and the sea surface temperature. Both applied the algorithm developed for the JAXA's Earth observation satellites, including the GCOM-C ( Global Change Observation Mission – Climate) satellite, in order to produce, in the future, datasets that are consistent between the satellites and can compensate each other's observations.
The aerosol property product (Figure 11) is being produced every 10 minutes in the daytime with a spatial resolution of 5 km. The current product is a beta version and will increase the quality through the ground validation.

- There are two kinds of SST (Sea Surface Temperature) products: an ordinary product and a nighttime product. The ordinary SST product (Figure 12) is a dataset produced every 10 minutes, regardless of day or night, with the spatial resolution of 2 km. In order to reduce the missing area by clouds, hourly averaged products are also created. The nighttime SST product uses Band 7 (3.9 µm wavelength) and, although it can only be retrieved at nighttime, its advantage is in its high accuracy. The dataset of the nighttime SST is an hourly averaged product with a spatial resolution of 2 km.

- During the commissioning phase, Himawari-8's capacity for superior Earth monitoring with multi-band, high-resolution and high-frequency observation was verified. JMA firmly believes that Himawari-8 will open the door to a new generation of satellite meteorology, and that it will contribute to the prevention and mitigation of weather-related disasters in the East Asia and Western Pacific regions as past satellites have done.

• July 1, 2015: JMA started Himawari-8 imagery dissemination via the HimawariCast service at 02:00 UTC on 1 July 2015, prior to Himawari-8 officially enters operation on 7 July. 31)

• In early 2015, Himawari-8 is testing and checking all systems in orbit and is scheduled to start operation in mid-2015. 32)

• On December 18, 2014, the first images from all 16 bands of the AHI (Advanced Himawari Imager) were captured by JMA's Himawari-8 next-generation geostationary meteorological satellite. 33)

• Himawari-8, entered the geostationary orbit on October 16, 2014 as planned. The satellite is expected to start operation in mid-2015 after the completion of in-orbit testing and checking of the overall system including related ground facilities. 34)

The functions and specifications of the Himawari-8 and -9 sensor complement are notably improved from those of the on-board imager of MTSAT. The Himawari-8 and -9 spacecraft carry the AHI (Advanced Himawari Imager) instrument to enable enhanced nowcasting, NWP (Numerical Weather Prediction) and environment monitoring. 36)37)

Figure 15: Enhancement of the observation function of Himawari-8/9 when compared to that of MTSAT-1R/2 (image credit: JMA)

AHI (Advanced Himawari Imager):

AHI is an ABI (Advanced Baseline Imager) class instrument, designed and developed at Exelis Inc. of Rochester, N.Y., and similar to the one that will be integrated onto the GOES-R spacecraft series of NASA/NOAA. - Note: In May 2015, Harris Corp. of Melbourne, FL. acquired Exelis Inc. of Fort Wayne, IN.38)39)

In November 2009, MELCO selected Exelis (former ITT Space Systems) of Rochester, N.Y. to build the imaging systems for two geostationary satellites, Himawari-8 and -9, of JMA. 40)41)

ABI and AHI both have 16 spectral channels in the visible and infrared spectrum, which is a significant increase in the number of spectral channels in comparison to heritage instruments. The two instruments have similar spectral bands with two main differences: ABI includes a 1.38 µm channel (for cirrus cloud detection), while this channel is replaced with a 0.51 µm channel (green band – to produce color composite imagery) on AHI (Ref.12) .

The AHI instrument provides the following general characteristics:

• Multi-purpose imagery for weather watch, NWP utilization and environment monitoring; and wind derivation by tracking clouds and water vapor features

- Spacelook collected at least every 30 s (automatically collected as part of every Full Disk swath)

- Blackbody (ICT) observed at start of each timeline

- Solar calibration scheduled when needed.

Onboard microvibration measures for AHI pointing error reduction:

One of the greatest obstacles to achieve high pointing accuracy is microvibration, which is induced by the dozens of the disturbance sources inside the satellite; examples include reaction wheels, mechanical gyros, and coolers. In order to satisfy the requirement, an evaluation of the influence of microvibration before launch is necessary. 43)

In order for the AHI to achieve high accuracy observations, the strict LOS (Line of Sight) pointing error is required. The LOS pointing error requirements for the AHI are shown in Table 7. The influence of the satellite bus system is considered in the requirements. Therefore, in order to satisfy the requirements for LOS pointing error, a high accuracy attitude control system, technology for reducing the influence of microvibration, and a low thermal expansion optical bench, etc. are adopted.

Pointing error classification

Requirement (time)

Main cause

LOS of
pointing error
of AHI

Attitude angle
error of AHI

Bias

-

-

Drift

14 µradp-p (600 s)

Alignment between IRU and optical bench,
Relative thermal deformation between IRU and STT

In addition to the conventional attitude determination system for attitude control, the high accuracy and broadband attitude determination system of the optical bench is provided for correcting images for the ground system of the Himawari-8 and -9. The attitude determination system of the optical bench functions in combination with the data from the STT (Star Tracker), IRU (Inertial Reference Unit), ARS (Angular Rate Sensor), and ACC (Accelerometer) installed on the optical bench.

Some measures were taken to reduce the influence of microvibration induced with disturbance sources. Low disturbance RWAs (Reaction Wheel Assemblies) are adopted, and an IRU (mechanical gyro), which generates the least level of disturbance, was selected. However, the LOS pointing error of a mission sensor is not only induced by disturbances generated from the disturbance sources discussed previously, but is also affected by characteristics of the satellite structure. Therefore, in the early development phase of the Himawari-8, the disturbance analysis was conducted, using transfer functions calculated by finite element analysis, and the data of disturbance sources, and in the final development phase, the microvibration test was conducted using the protoflight model of the Himawari-8.

In summary, the motion of the optical bench, induced by disturbance sources installed in the Himawari-8, was evaluated with the data acquired in both the ground test and orbit. The results showed that the vibration level predicted from the ground test data, almost exactly coincided with the data measured in orbit. The health of the onboard sensors was confirmed by comparing the ground test data with the in-orbit data. It was confirmed that the dominant disturbance sources in the Himawari-8 were the IRU and the cooler in the AHI. However, the microvibration level of Himawari-8 was still very quiet, compared to the ESA and JAXA satellite models.

SEDA (Space Environment Data Acquisition Monitor)

SEDA will measure the radiation to which Himawari-8/-9 satellites are exposed in their geostationary Earth orbits. SEDA's design is basically identical to the EMU (Environmental Monitoring Unit) developed for the European satellite navigation system Galileo.

The Himawari-8/-9 missions support the collection of surface-based observation data obtained by ground segments with corresponding on-board DCSs (Data Collection System) in the same manner as provided by the MTSAT series. DCP channels relay their data from the DCPs through a UHF transponder, which outputs the Ka-band signal.

Ground segment:

The Himawari-8 and -9 ground segment, designed, built and installed by MELCO, consists of antennas of 9 m diameter and radio frequency and satellite control equipment installed at the main unit in Hiki-gun, Saitama Prefecture, and the sub unit in Ebetsu, Hokkaido. 44)

In August 2010, Himawari Operation Enterprise was established as Special Purpose Company to operate the Himawari series spacecraft. This consortium is composed of Mitsubishi UFJ Lease & Finance Company Limited (representative company, management of office), NS Solutions Corporation (development of ground facilities, systems and maintenance work), and Space Engineering Development Co., Ltd. (service delivery), and has contracted this project with JMA in 2010 for the duration of 20 years until the end of March 2030 ((4 year and 7 month development period, 15 year maintenance and service delivery period).

Legend to Figure 26: Himawari-8/9 will not carry equipment for direct dissemination. Instead, all imagery derived from the satellites will be distributed to NMHSs (National Meteorological and Hydrological Services) via an Internet cloud service (see (a) in the Figure 26). Full sets of data will also be provided to researchers via archive servers operated by the Japanese Science Group on a best-effort basis (b). The HimawariCast service will additionally disseminate primary sets of imagery via a communication satellite using Digital Video Broadcasting — Satellite — Second Generation (DVB-S2) technology (c). Note: NREN (National Research and Education Network).

In addition, JMA will continue the current online imagery distribution service; WIS Portal (d) and the JDDS (JMA Data Dissemination System), (e) even after Himawari-8 takes over as the main operational satellite.

The HimawariCast service:

• MTSAT-2 imagery dissemination via the HimawariCast service began at 03:00 UTC on 29 January 2015. 46)47)48)

- MTSAT-2 imagery is currently provided directly via MTSAT-1R through the L-band frequency HRIT (High-Rate Information Transmission) and LRIT (Low-Rate Information Transmission) services. JMA will terminate these services in around November 2015. As a replacement of these services, JMA started the HimawariCast service which disseminates primary sets of imagery via a communication satellite from January 2015 onwards.

- The interval between full-disk observations by Himawari-8 will be 10 minutes, which is much shorter than the 30/60 minutes of the MTSAT series. The HimawariCast service will provide full-disk imagery with this high 10-minute observation frequency.

- JMA successfully launched Himawari-8 in October 2014 and will switch over operations from MTSAT-2 in mid-2015.

- The HimawariCast service is disseminating imagery of the current operational satellite, MTSAT-2, and Himawari-8 imagery will be disseminated after Himawari-8 becomes operational. JMA has a plan to disseminate Himawari-8 imagery on a trial basis while MTSAT-2 is in operation.

Figure 27: : Schedule for transition from the MTSAT HRIT/LRIT service to the HimawariCast service (image credit: JMA)

The JCSAT-2A communication satellite located at 154 ºE is used to broadcast data for the HimawariCast service. The JCSAT-2B unit will then take over from JCSAT-2A as the communication satellite in Q4 of 2015 at the same location. HimawariCast users will need to prepare for the transition from JCSAT-2A to JCSAT-2B during a dual operation period (approx. 1 week) of JCSAT-2A and JCSAT-2B.

The HimawariCloud service:

To distribute the enormous volumes of Himawari-8/9 imagery that will be produced, JMA will establish an Internet cloud service (HimawariCloud) mainly for NMHSs (National Meteorological and Hydrological Services) in the East Asia and Western Pacific regions.

Table 9 shows the tentative data set to be distributed via the cloud service. Himawari Standard Data will be used to create all products related to Himawari-8/9 as master data from all 16 bands with the finest spatial resolution. The true-color images will be provided in Portable Network Graphics (PNG) format. For rapid scanning observation, imagery in Network Common Data Form (NetCDF) will also be created and distributed.

Table 9: The tentative data set to be distributed via the HimawariCloud

Each NMHS will be able to access the cloud and get data using an HTTP 1.1 client such as a Web browser or Wget. It is important to note that an Internet connection with a speed of at least 25 Mbit/s will be required to download all Himawari Standard Data. These data will be separately created for each band and divided into 10 segments from north to south so that NMHSs can select only the files necessary for their operation.

Overview of the Himawari-8/9 ground segment and operations:

The Himawari-8/9 satellites and their ground stations will be operated by Himawari Operation Enterprise Corporation (HOPE) — a special-purpose company (SPC) established under JMA's Private Finance Initiative (PFI) project. Observation data from the AHI (Advanced Himawari Imager) and DCP (Data Collection Platform) data will be transmitted through HOPE to JMA, which will process the information and disseminate products to users (Figure 28).

Site diversity: Himawari-8/9 will use the Ka-band for AHI and DCP data downlink frequency, and will adopt the Ku-band for TT&C (Telemetry, Tracking and Command). To minimize the potential for negative data impacts from these bands, which both tend to be affected by rain attenuation, site diversity will be introduced by establishing two antenna sites (ASs). One will be in the Kanto region (the primary station) and the other will be in the Hokkaido region (the secondary station), meaning that their locations will be around 800 km apart and in different weather conditions. The two data centers (DCs) for processing data received will also be located in the Kanto and Hokkaido regions.

Operation by HOPE: HOPE will operate the ASs and DCs. The ASs will house transmitting/receiving equipment including antennas with a diameter of 9 m, and the DCs will have equipment for satellite control and AHI/DCP data processing. AHI and DCP data received at ASs will be transmitted to DCs, where the former will be processed to create level 1a data (raw data with calibration/navigation parameters attached) and the latter will be converted for use with JMA's telecommunications system. The processed data will be transmitted to JMA's Meteorological Satellite Center (Tokyo) and its Osaka Regional Headquarters (Osaka). In the event that the primary station becomes dysfunctional, the secondary station will take over its operations.

Operation by JMA: The MSC (Meteorological Satellite Center) will receive data from both the primary and secondary stations for preprocessing, and Himawari Standard Data, HRIT files and edited DCP data will then be produced and provided to users. The Osaka Regional Headquarters will receive data from the secondary station only. In the event that the MSC system becomes dysfunctional (e.g., due to a malfunction caused by a natural disaster), data/products will be provided from Osaka.

The information compiled and edited in this article was provided byHerbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (herb.kramer@gmx.net).